Why PortoAlegre? Because in recent years the city has become something of a symbol. The capital of the Brazil's southernmost state, Rio Grande do Sul, on the border with Argentina and Uruguay, Porto Alegre is a kind of social laboratory, and as such is being closely watched by international experts in urban planning.

For 14 years now it has been governed in new and original ways by a leftwing coalition led by the Brazilian Workers' Party (PT). In a whole range of sectors (housing, public transport, highways, garbage collection, clinics, hospitals, sewerage, environment, social housing, literacy, schooling, culture, law and order etc) the city has made spectacular progress. The key to this success has been its "participatory budget" (orçamento participativo), which makes it genuinely possible for the inhabitants of any given neighbourhood to define concretely and democratically where municipal funds are to be allocated. In other words, the people of the city decide what kind of infrastructures they want to create or improve, and the system enables them to follow in detail how work is progressing and how the money is being spent. This leaves less room for corruption and the siphoning of public funds, and urban investment is more likely to match the majority desires of the city's population.